Help with school district stuff..;o?

me and my family were planing to move to south milwauke (WI). we currently live in oak creek(wi). im having this HUGE problem. if i move to south milwaukee, even though im out of the school disctrics, can i still go to east middle school(the school ive been going to)??my mom says that i HAVE to go to s.m..and she says that if i reallllyyy want to go to east, she would have to pay like $4,000!!! now idk if shes lying and stuff. but i just want to know if i can to to east...!! help?(: